1. Field of the Invention
The present invention relates to stump and wood chipping disintegrators and more particularly to a knife assembly for such disintegrators.
2. Description of the Related Art
Clearing of wooded terrain for building construction or highway purposes has been greatly aided by the development of practical chipping equipment. The trunks, limbs and tops of trees and brush can be chipped for fuel, paper manufacturing, chipboard fabrication and other uses. Alternatively, tree trunks can be separated for making lumber and plywood, while the branches and tops are chipped for fuel or the like.
The tree stumps, however, are not as readily processed or disposed of as the upper portions of the trees. Stumps are extremely difficult to chip and destructive of machinery. Often there are stones lodged in the roots in addition to large quantities of dirt. The stump wood itself has roots extending in many directions and possessing differing grain patterns.
Recently, machines have been developed for the effective chipping or disintegrating of stumps, as exemplified by the disclosure of U.S. Pat. No. 4,736,781, issued Apr. 12, 1988, and entitled "Stump Disintegrator." Briefly described, the apparatus shown therein has a trough forming a stump support, a chipping disk at one end of the trough with chipping blades projecting from the face of the disk at varying radial distances from the rotational axis of the disk, and a driven ram plate at the other end of the trough for forcing stumps toward the disk. The chipping disk is provided with a plurality of openings or pockets in which the chipping blades are carried.
The chipping blades of U.S. Pat. No. 4,736,781 comprise rather complex assemblies of replaceable carbide knife blade inserts carried on special blade holders. The holders include an outer holder body with peripheral holes for bolting the holders to the rear face of the chipping disk so that the holders extend through the pockets. The carbide blade is dovetailed into the holder. In order to firmly hold the blade in place and allow for its adjustment, there is an arrangement of a wedge, a differential threaded fastener, a stop screw, an inner holder member, and a fastener bolt. Each of these several parts is subject to wear and damage.
Therefore, there is a heretofore unmet need for a stump chipper knife assembly which is of simple and economical construction and which is easily maintained.